O (annealed)
Fully soft with a defined maximum strength. Order O when the bar will be bent, upset or cold-headed, for example into U-bolts, shackle pins or formed handrail returns.
Marine · Al-Mg extruded round bar
5083 & 5383 Marine Aluminium Round Bar
5083 round bar is the standard aluminium bar for shipbuilding fittings that sit in or near seawater: it resists marine corrosion, welds without losing a heat-treated temper and is one of the few extruded grades covered by IACS class rules for hull structure. 5383 is its higher-strength, more corrosion-resistant development. Metline supplies both in O, H111 and H112, cut and certified, to yards and fabricators worldwide.
- Alloys
- 5083 · 5383 (Al-4.5Mg-Mn)
- Tempers
- O, H111, H112
- Diameter
- About 8 – 320 mm
- Standards
- ASTM B221 · EN 755 · IACS W25
Why 5083 is the default marine round bar
5083 contains about 4.5 % magnesium with manganese and chromium. It gets its strength from magnesium in solid solution and from cold work, not from heat treatment, so welding does not wipe out a carefully aged temper the way it does with 6061 or 6082.
That single fact explains its place in shipbuilding. A bar welded into a hull, deck or tank keeps most of its strength around the weld, and the alloy's very low copper content gives it some of the best resistance to seawater of any structural aluminium. Round bar in 5083 is machined into stern-tube and rudder-stock bushes, bollard and cleat bodies, hinge pins, pad eyes, flange blanks and the many small bosses that are welded into 5083 plate structures.
5383 was developed in the 1990s as an optimised 5083. Tighter limits on iron and silicon, a higher manganese range and a zirconium addition give roughly 15 % more proof strength after welding, better fatigue performance and improved resistance to intergranular and exfoliation corrosion. Both alloys appear side by side in the extrusion table of IACS UR W25, the unified class requirement that the major classification societies apply to aluminium for hulls.
5083 and 5383 chemical composition (wt %)
5083 limits are the registered Aluminum Association values, shared by ASTM B221, EN 573-3 (EN AW-5083, AlMg4.5Mn0.7) and IACS UR W25. The 5383 column shows how the alloy was tightened and enriched.
| Element | 5083 min | 5083 max | 5383 limits | Effect |
|---|---|---|---|---|
| Silicon (Si) | — | 0.40 | ≤ 0.25 | Lower Si and Fe in 5383 improve toughness and corrosion |
| Iron (Fe) | — | 0.40 | ≤ 0.25 | Impurity |
| Copper (Cu) | — | 0.10 | ≤ 0.20 | Held low for seawater resistance |
| Manganese (Mn) | 0.40 | 1.0 | 0.7 – 1.0 | Strength and grain control |
| Magnesium (Mg) | 4.0 | 4.9 | 4.0 – 5.2 | Main strengthening element |
| Chromium (Cr) | 0.05 | 0.25 | ≤ 0.25 | Stress-corrosion resistance |
| Zinc (Zn) | — | 0.25 | ≤ 0.40 | Small Zn in 5383 helps corrosion behaviour |
| Titanium (Ti) | — | 0.15 | ≤ 0.15 | Grain refiner |
| Zirconium (Zr) | — | — | ≤ 0.20 | Raises recrystallisation temperature and weld-zone strength |
| Others, each / total | — | 0.05 / 0.15 | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | Remainder |
Each delivery carries a certificate reporting the actual cast analysis. Check that magnesium on a "5083" certificate lies between 4.0 and 4.9 %.
Mechanical properties of 5083 / 5383 round bar
The table gives the minimum values for extruded products in IACS UR W25, which match ASTM B221 and EN 755-2 for 5083. These are the numbers class surveyors and designers work to. Elongation is measured on 50 mm gauge up to 12.5 mm diameter and on 5d above that.
| Alloy and temper | Tensile strength Rm | Proof strength Rp0.2 (min) | Elongation A50 / A5d (min) |
|---|---|---|---|
| 5083-O | 270 – 350 MPa | 110 MPa | 14 % / 12 % |
| 5083-H111 | ≥ 275 MPa | 165 MPa | 12 % / 10 % |
| 5083-H112 | ≥ 270 MPa | 110 MPa | 12 % / 10 % |
| 5383-O / H111 | ≥ 290 MPa | 145 MPa | 17 % / 17 % |
| 5383-H112 | ≥ 310 MPa | 190 MPa | 13 % (A5d) |
Typical as-extruded 5083 bar tests at about 290 – 300 MPa tensile and 130 – 150 MPa proof, with Brinell hardness around 75 HB. For welded design, the as-welded minimum tensile strength of 5083 is about 275 MPa, which is why designers can use nearly the full parent-metal value across butt welds.
Physical properties (5083)
- Density
- 2.66 g/cm³ (0.096 lb/in³)
- Modulus of elasticity
- About 70 GPa (10,200 ksi)
- Thermal conductivity
- About 117 – 120 W/m·K
- Electrical conductivity
- About 29 % IACS
- Coefficient of thermal expansion
- About 23.8 µm/m·°C (20 – 100 °C)
- Melting range
- About 591 – 638 °C
- Magnetic
- Non-magnetic
O, H111 or H112: which temper to order
H111
Annealed, then lightly strain-hardened by straightening. Proof strength is higher than O (165 MPa minimum for 5083) while ductility stays good.
H112
As extruded, with guaranteed minimum properties. The usual choice for bar that will be machined into fittings and bushes.
No heat-treated tempers
5083 and 5383 cannot be solution treated and aged. Any T-temper on a 5083 order is an error to query before production.
Sensitisation limit
With more than 3 % magnesium, both alloys should not be used where metal temperature stays above about 65 °C for long periods, such as next to engine exhausts.
Plate tempers
H116 and H321, the corrosion-tested tempers, apply to rolled plate rather than extruded bar; see the 5083 marine plate page.
Standards, class approval and equivalent designations
For classed vessels, extruded 5083 and 5383 must come from works approved by the classification society for those grades, with tests witnessed or reviewed as the society requires. IACS UR W25 lists 5083, 5383, 5059 and 5086 for extruded bars and sections in O, H111 and H112, together with 6005A, 6061 and 6082 in T5 or T6. DNV, ABS, Lloyd's Register, Bureau Veritas, ClassNK, KR and CCS apply these requirements through their own material rules. Tell us the society on your order so certification can be arranged from an approved source.
| System | Designation | Typical bar standard |
|---|---|---|
| Aluminum Association / ASTM | 5083, 5383 | ASTM B221 (extruded), ASTM B211 (cold-finished, 5083) |
| UNS | A95083 | — |
| European (EN) | EN AW-5083 (AlMg4.5Mn0.7), EN AW-5383 | EN 755-2 / -3 extruded, EN 754 drawn |
| German Werkstoff | 3.3547 (5083) | DIN EN 755 |
| ISO | AlMg4.5Mn0.7 | ISO 6362 |
| Japan (JIS) | A5083BE | JIS H4040 |
| China (GB) | 5083, 5383 | GB/T 3191 extruded bar |
| Class rules | 5083 / 5383 O, H111, H112 | IACS UR W25 and the rules of each society |
5083 round bar sizes and weights
Supply range
- Diameter
- About 8 – 320 mm extruded; small diameters also cold-drawn for closer tolerance
- Length
- 3000, 4000 or 6000 mm standard; random lengths or cut pieces on request
- Tempers
- O, H111, H112 (5083); O, H111, H112 (5383)
- Finish
- Mill finish; peeled or turned bar available for large diameters
- Processing
- Saw cutting to length, end facing and deburring
Large diameters above about 250 mm come from large extrusion presses or from forged billet; ask early if your part needs them.
Weight of round bar per metre is π/4 × d² × 2.66 ÷ 1000 kg with d in millimetres. The bar weight calculator handles any size and other shapes.
| Diameter (mm) | kg per metre | kg per 3 m bar | kg per 6 m bar |
|---|---|---|---|
| 10 | 0.209 | 0.63 | 1.3 |
| 12 | 0.301 | 0.90 | 1.8 |
| 16 | 0.535 | 1.60 | 3.2 |
| 20 | 0.836 | 2.51 | 5.0 |
| 25 | 1.31 | 3.92 | 7.8 |
| 30 | 1.88 | 5.64 | 11.3 |
| 40 | 3.34 | 10.03 | 20.1 |
| 50 | 5.22 | 15.67 | 31.3 |
| 60 | 7.52 | 22.56 | 45.1 |
| 70 | 10.24 | 30.71 | 61.4 |
| 80 | 13.37 | 40.11 | 80.2 |
| 100 | 20.89 | 62.67 | 125.3 |
| 120 | 30.08 | 90.25 | 180.5 |
| 150 | 47.01 | 141.02 | 282.0 |
| 180 | 67.69 | 203.07 | 406.1 |
| 200 | 83.57 | 250.70 | 501.4 |
| 250 | 130.57 | 391.72 | 783.4 |
| 300 | 188.02 | 564.07 | 1128.1 |
Diameter tolerance, straightness and inspection
Extruded 5083 bar is normally supplied to the tolerance tables of EN 755-3 or the equivalent GB/T and ASTM tables. 5083 and 5383 fall in the higher-magnesium group, so the wider column applies; cold-drawn bar is held much tighter.
| Size band (mm) | Typical tolerance, lower-Mg grades (mm) | Typical tolerance, higher-Mg grades (mm) |
|---|---|---|
| 8 – 18 | ±0.22 | ±0.30 |
| over 18 – 25 | ±0.25 | ±0.35 |
| over 25 – 40 | ±0.30 | ±0.40 |
| over 40 – 50 | ±0.35 | ±0.45 |
| over 50 – 65 | ±0.40 | ±0.50 |
| over 65 – 80 | ±0.45 | ±0.70 |
| over 80 – 100 | ±0.55 | ±0.90 |
| over 100 – 120 | ±0.65 | ±1.0 |
| over 120 – 150 | ±0.80 | ±1.2 |
| over 150 – 180 | ±1.00 | ±1.4 |
| over 180 – 220 | ±1.15 | ±1.7 |
| over 220 – 270 | ±1.3 | ±2.0 |
| over 270 – 320 | ±1.6 | ±2.5 |
Form and inspection
- Straightness
- Typically no more than 0.8 – 1.5 mm in any 300 mm, depending on diameter, and about 2 – 3 mm per metre of length overall
- Length
- Fixed lengths supplied plus-only, typically +5 to +12 mm depending on size and length
- Ultrasonic testing
- Available on request for large-diameter bar used in rudder stocks, shafts or pressure parts
- Corrosion testing
- ASTM G66 / G67 testing is a plate requirement in UR W25; it can be agreed for bar where a specification asks for it
- Certification
- EN 10204 3.1 mill certificate; class certificate when ordered from an approved works
Machining, welding and finishing 5083 bar
Machining
Soft and somewhat gummy. Use sharp, polished carbide with high positive rake, large chip gullets and plenty of coolant to prevent built-up edge. H112 and H111 give a cleaner finish than O.
Welding
TIG and MIG weld readily. ER5183 is the usual filler for matching strength; ER5556 gives a little more; ER5356 suits lower-stressed joints. Avoid 4xxx fillers, which form brittle Mg2Si in the weld.
Forming
O and H111 bar bends and upsets well at room temperature. Avoid hot forming in the 150 – 300 °C range, which can sensitise the alloy.
Galvanic contact
Isolate from stainless steel, bronze and copper-nickel with insulating bushes, sleeves and sealant. Never use copper-based antifouling on bare aluminium.
Anodising and painting
Takes sulphuric anodising for a protective, uniform finish, though slightly darker than 6xxx alloys. Most underwater fittings are left bare or painted as part of the hull system.
Low temperature
Strength and toughness increase as temperature falls, so 5083 is used for cryogenic and LNG equipment as well as cold-water vessels.
Where marine yards use 5083 / 5383 round bar
- Hull and deck fittings: bollards, cleats, fairleads, pad eyes and towing points machined from bar and welded to 5083 plate
- Steering and propulsion: rudder bearing housings, bushes, stern-tube flanges and shaft-seal carriers
- Hinges and closures: hinge pins, hatch dogs, door handles and wedges on watertight closures
- Piping: flange blanks, weld bosses and pipe supports in seawater, fuel and bilge systems
- Offshore and aquaculture: fish-farm pen fittings, gangway pins, buoy and mooring hardware
- Cryogenic and tank equipment: nozzles and machined parts for LNG and pressure equipment
A typical example is a welded aluminium workboat: the hull is 5083-H116 plate, longitudinal stiffeners are 5083 or 6082 extrusions, and every boss, lifting eye and bollard base is turned from 5083-H112 round bar so that the whole welded structure shares one corrosion behaviour and one filler wire.
5083 and 5383 bar compared with 5086, 6082 and 5A06
| Property | 5083-H112 | 5383-H112 | 5086-H112 | 6082-T6 | 5A06-H112 |
|---|---|---|---|---|---|
| Min tensile (extruded) | 270 MPa | 310 MPa | 240 MPa | 310 MPa | 315 MPa |
| Min proof (extruded) | 110 MPa | 190 MPa | 95 MPa | 260 MPa | 155 MPa |
| Strength after welding | High | Highest of group | High | Large HAZ loss | High |
| Seawater immersion | Excellent | Excellent | Excellent | Good, with coating | Very good |
| Machinability | Fair | Fair | Fair | Very good | Fair |
| Listed in UR W25 (extruded) | Yes | Yes | Yes | Yes (T5/T6) | No |
Choose 6082-T6 for unwelded or above-water parts that need high proof strength and easy machining. Choose 5083 where parts are welded and wet, and 5383 when you need extra welded strength or fatigue life. 5A06 is mainly used on projects designed to GB or GOST standards.
How to order 5083 marine round bar
- SpecifyAlloy and temper, diameter and length or cut pieces, quantity and the governing standard with its edition (ASTM B221, EN 755-2, GB/T 3191 or a class rule). If the vessel is classed, name the society and whether a class certificate is required.
- ConfirmWe confirm the standard and tolerance class can be met, which tests are included (tensile, chemistry, corrosion tests where the standard calls for them) and the delivery terms: EXW, FOB, CIF or DAP.
- InspectMaterial is checked for dimensions, straightness, twist and surface condition before packing; third-party or class surveyor inspection can be arranged on request.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing the cast analysis and mechanical results, traceable by cast or lot number.
- Pack and shipBars or plates are bundled or cased with moisture protection, marked with alloy, temper, size and lot, and shipped by sea or air to your port or yard.
References and standards
- IACS UR W25 – Aluminium alloys for hull construction and marine structure
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes
- EN 755-2 – Aluminium and aluminium alloys: extruded rod/bar, tube and profiles, mechanical properties
- EN 573-3 – Aluminium and aluminium alloys: chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
5083 marine aluminium (aluminum) round bar: FAQs
Is 5083 round bar approved for classed vessels?
The alloy is. IACS UR W25 lists extruded 5083 and 5383 in O, H111 and H112 for hull construction. Each lot must come from a works approved by your classification society and carry its certificate if the order requires it.
What is the difference between 5083 and 5383 bar?
5383 is an optimised 5083 with lower iron and silicon, more manganese and a zirconium addition. Its minimum proof strength in H112 is 190 MPa against 110 MPa for 5083, and it keeps more strength after welding with better corrosion and fatigue resistance.
Can 5083 bar be heat treated?
No. It is a non-heat-treatable alloy. It can be annealed to O or stabilised, but strength comes only from magnesium and cold work, which is also why welds do not destroy its properties.
Which filler wire is used to weld 5083 round bar?
ER5183 is standard for strength matching. ER5556 gives slightly higher weld strength; ER5356 is acceptable for lightly stressed joints. Do not use ER4043 on 5083.
Is 5083 bar suitable near engines or exhausts?
Not for long-term service above about 65 °C. At those temperatures high-magnesium alloys can become sensitised and prone to intergranular corrosion. Use 5454 or a 6xxx alloy for warm locations.
Can you supply 5083 bar cut to length with certificates?
Yes. Metline supplies 5083 and 5383 round bar in full lengths or cut pieces with an EN 10204 3.1 certificate, and arranges class or third-party inspection on request, for delivery worldwide.
Need 5083 or 5383 round bar for a vessel?
Send diameters, temper, quantities, the governing standard and the class society. We will reply with availability, certification and a delivered price.
